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Linux/lib/bootconfig.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * Extra Boot Config
  4  * Masami Hiramatsu <mhiramat@kernel.org>
  5  */
  6 
  7 #define pr_fmt(fmt)    "bootconfig: " fmt
  8 
  9 #include <linux/bootconfig.h>
 10 #include <linux/bug.h>
 11 #include <linux/ctype.h>
 12 #include <linux/errno.h>
 13 #include <linux/kernel.h>
 14 #include <linux/memblock.h>
 15 #include <linux/printk.h>
 16 #include <linux/string.h>
 17 
 18 /*
 19  * Extra Boot Config (XBC) is given as tree-structured ascii text of
 20  * key-value pairs on memory.
 21  * xbc_parse() parses the text to build a simple tree. Each tree node is
 22  * simply a key word or a value. A key node may have a next key node or/and
 23  * a child node (both key and value). A value node may have a next value
 24  * node (for array).
 25  */
 26 
 27 static struct xbc_node *xbc_nodes __initdata;
 28 static int xbc_node_num __initdata;
 29 static char *xbc_data __initdata;
 30 static size_t xbc_data_size __initdata;
 31 static struct xbc_node *last_parent __initdata;
 32 static const char *xbc_err_msg __initdata;
 33 static int xbc_err_pos __initdata;
 34 static int open_brace[XBC_DEPTH_MAX] __initdata;
 35 static int brace_index __initdata;
 36 
 37 static int __init xbc_parse_error(const char *msg, const char *p)
 38 {
 39         xbc_err_msg = msg;
 40         xbc_err_pos = (int)(p - xbc_data);
 41 
 42         return -EINVAL;
 43 }
 44 
 45 /**
 46  * xbc_root_node() - Get the root node of extended boot config
 47  *
 48  * Return the address of root node of extended boot config. If the
 49  * extended boot config is not initiized, return NULL.
 50  */
 51 struct xbc_node * __init xbc_root_node(void)
 52 {
 53         if (unlikely(!xbc_data))
 54                 return NULL;
 55 
 56         return xbc_nodes;
 57 }
 58 
 59 /**
 60  * xbc_node_index() - Get the index of XBC node
 61  * @node: A target node of getting index.
 62  *
 63  * Return the index number of @node in XBC node list.
 64  */
 65 int __init xbc_node_index(struct xbc_node *node)
 66 {
 67         return node - &xbc_nodes[0];
 68 }
 69 
 70 /**
 71  * xbc_node_get_parent() - Get the parent XBC node
 72  * @node: An XBC node.
 73  *
 74  * Return the parent node of @node. If the node is top node of the tree,
 75  * return NULL.
 76  */
 77 struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node)
 78 {
 79         return node->parent == XBC_NODE_MAX ? NULL : &xbc_nodes[node->parent];
 80 }
 81 
 82 /**
 83  * xbc_node_get_child() - Get the child XBC node
 84  * @node: An XBC node.
 85  *
 86  * Return the first child node of @node. If the node has no child, return
 87  * NULL.
 88  */
 89 struct xbc_node * __init xbc_node_get_child(struct xbc_node *node)
 90 {
 91         return node->child ? &xbc_nodes[node->child] : NULL;
 92 }
 93 
 94 /**
 95  * xbc_node_get_next() - Get the next sibling XBC node
 96  * @node: An XBC node.
 97  *
 98  * Return the NEXT sibling node of @node. If the node has no next sibling,
 99  * return NULL. Note that even if this returns NULL, it doesn't mean @node
100  * has no siblings. (You also has to check whether the parent's child node
101  * is @node or not.)
102  */
103 struct xbc_node * __init xbc_node_get_next(struct xbc_node *node)
104 {
105         return node->next ? &xbc_nodes[node->next] : NULL;
106 }
107 
108 /**
109  * xbc_node_get_data() - Get the data of XBC node
110  * @node: An XBC node.
111  *
112  * Return the data (which is always a null terminated string) of @node.
113  * If the node has invalid data, warn and return NULL.
114  */
115 const char * __init xbc_node_get_data(struct xbc_node *node)
116 {
117         int offset = node->data & ~XBC_VALUE;
118 
119         if (WARN_ON(offset >= xbc_data_size))
120                 return NULL;
121 
122         return xbc_data + offset;
123 }
124 
125 static bool __init
126 xbc_node_match_prefix(struct xbc_node *node, const char **prefix)
127 {
128         const char *p = xbc_node_get_data(node);
129         int len = strlen(p);
130 
131         if (strncmp(*prefix, p, len))
132                 return false;
133 
134         p = *prefix + len;
135         if (*p == '.')
136                 p++;
137         else if (*p != '\0')
138                 return false;
139         *prefix = p;
140 
141         return true;
142 }
143 
144 /**
145  * xbc_node_find_child() - Find a child node which matches given key
146  * @parent: An XBC node.
147  * @key: A key string.
148  *
149  * Search a node under @parent which matches @key. The @key can contain
150  * several words jointed with '.'. If @parent is NULL, this searches the
151  * node from whole tree. Return NULL if no node is matched.
152  */
153 struct xbc_node * __init
154 xbc_node_find_child(struct xbc_node *parent, const char *key)
155 {
156         struct xbc_node *node;
157 
158         if (parent)
159                 node = xbc_node_get_child(parent);
160         else
161                 node = xbc_root_node();
162 
163         while (node && xbc_node_is_key(node)) {
164                 if (!xbc_node_match_prefix(node, &key))
165                         node = xbc_node_get_next(node);
166                 else if (*key != '\0')
167                         node = xbc_node_get_child(node);
168                 else
169                         break;
170         }
171 
172         return node;
173 }
174 
175 /**
176  * xbc_node_find_value() - Find a value node which matches given key
177  * @parent: An XBC node.
178  * @key: A key string.
179  * @vnode: A container pointer of found XBC node.
180  *
181  * Search a value node under @parent whose (parent) key node matches @key,
182  * store it in *@vnode, and returns the value string.
183  * The @key can contain several words jointed with '.'. If @parent is NULL,
184  * this searches the node from whole tree. Return the value string if a
185  * matched key found, return NULL if no node is matched.
186  * Note that this returns 0-length string and stores NULL in *@vnode if the
187  * key has no value. And also it will return the value of the first entry if
188  * the value is an array.
189  */
190 const char * __init
191 xbc_node_find_value(struct xbc_node *parent, const char *key,
192                     struct xbc_node **vnode)
193 {
194         struct xbc_node *node = xbc_node_find_child(parent, key);
195 
196         if (!node || !xbc_node_is_key(node))
197                 return NULL;
198 
199         node = xbc_node_get_child(node);
200         if (node && !xbc_node_is_value(node))
201                 return NULL;
202 
203         if (vnode)
204                 *vnode = node;
205 
206         return node ? xbc_node_get_data(node) : "";
207 }
208 
209 /**
210  * xbc_node_compose_key_after() - Compose partial key string of the XBC node
211  * @root: Root XBC node
212  * @node: Target XBC node.
213  * @buf: A buffer to store the key.
214  * @size: The size of the @buf.
215  *
216  * Compose the partial key of the @node into @buf, which is starting right
217  * after @root (@root is not included.) If @root is NULL, this returns full
218  * key words of @node.
219  * Returns the total length of the key stored in @buf. Returns -EINVAL
220  * if @node is NULL or @root is not the ancestor of @node or @root is @node,
221  * or returns -ERANGE if the key depth is deeper than max depth.
222  * This is expected to be used with xbc_find_node() to list up all (child)
223  * keys under given key.
224  */
225 int __init xbc_node_compose_key_after(struct xbc_node *root,
226                                       struct xbc_node *node,
227                                       char *buf, size_t size)
228 {
229         u16 keys[XBC_DEPTH_MAX];
230         int depth = 0, ret = 0, total = 0;
231 
232         if (!node || node == root)
233                 return -EINVAL;
234 
235         if (xbc_node_is_value(node))
236                 node = xbc_node_get_parent(node);
237 
238         while (node && node != root) {
239                 keys[depth++] = xbc_node_index(node);
240                 if (depth == XBC_DEPTH_MAX)
241                         return -ERANGE;
242                 node = xbc_node_get_parent(node);
243         }
244         if (!node && root)
245                 return -EINVAL;
246 
247         while (--depth >= 0) {
248                 node = xbc_nodes + keys[depth];
249                 ret = snprintf(buf, size, "%s%s", xbc_node_get_data(node),
250                                depth ? "." : "");
251                 if (ret < 0)
252                         return ret;
253                 if (ret > size) {
254                         size = 0;
255                 } else {
256                         size -= ret;
257                         buf += ret;
258                 }
259                 total += ret;
260         }
261 
262         return total;
263 }
264 
265 /**
266  * xbc_node_find_next_leaf() - Find the next leaf node under given node
267  * @root: An XBC root node
268  * @node: An XBC node which starts from.
269  *
270  * Search the next leaf node (which means the terminal key node) of @node
271  * under @root node (including @root node itself).
272  * Return the next node or NULL if next leaf node is not found.
273  */
274 struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
275                                                  struct xbc_node *node)
276 {
277         if (unlikely(!xbc_data))
278                 return NULL;
279 
280         if (!node) {    /* First try */
281                 node = root;
282                 if (!node)
283                         node = xbc_nodes;
284         } else {
285                 if (node == root)       /* @root was a leaf, no child node. */
286                         return NULL;
287 
288                 while (!node->next) {
289                         node = xbc_node_get_parent(node);
290                         if (node == root)
291                                 return NULL;
292                         /* User passed a node which is not uder parent */
293                         if (WARN_ON(!node))
294                                 return NULL;
295                 }
296                 node = xbc_node_get_next(node);
297         }
298 
299         while (node && !xbc_node_is_leaf(node))
300                 node = xbc_node_get_child(node);
301 
302         return node;
303 }
304 
305 /**
306  * xbc_node_find_next_key_value() - Find the next key-value pair nodes
307  * @root: An XBC root node
308  * @leaf: A container pointer of XBC node which starts from.
309  *
310  * Search the next leaf node (which means the terminal key node) of *@leaf
311  * under @root node. Returns the value and update *@leaf if next leaf node
312  * is found, or NULL if no next leaf node is found.
313  * Note that this returns 0-length string if the key has no value, or
314  * the value of the first entry if the value is an array.
315  */
316 const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
317                                                  struct xbc_node **leaf)
318 {
319         /* tip must be passed */
320         if (WARN_ON(!leaf))
321                 return NULL;
322 
323         *leaf = xbc_node_find_next_leaf(root, *leaf);
324         if (!*leaf)
325                 return NULL;
326         if ((*leaf)->child)
327                 return xbc_node_get_data(xbc_node_get_child(*leaf));
328         else
329                 return "";      /* No value key */
330 }
331 
332 /* XBC parse and tree build */
333 
334 static int __init xbc_init_node(struct xbc_node *node, char *data, u32 flag)
335 {
336         unsigned long offset = data - xbc_data;
337 
338         if (WARN_ON(offset >= XBC_DATA_MAX))
339                 return -EINVAL;
340 
341         node->data = (u16)offset | flag;
342         node->child = 0;
343         node->next = 0;
344 
345         return 0;
346 }
347 
348 static struct xbc_node * __init xbc_add_node(char *data, u32 flag)
349 {
350         struct xbc_node *node;
351 
352         if (xbc_node_num == XBC_NODE_MAX)
353                 return NULL;
354 
355         node = &xbc_nodes[xbc_node_num++];
356         if (xbc_init_node(node, data, flag) < 0)
357                 return NULL;
358 
359         return node;
360 }
361 
362 static inline __init struct xbc_node *xbc_last_sibling(struct xbc_node *node)
363 {
364         while (node->next)
365                 node = xbc_node_get_next(node);
366 
367         return node;
368 }
369 
370 static struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
371 {
372         struct xbc_node *sib, *node = xbc_add_node(data, flag);
373 
374         if (node) {
375                 if (!last_parent) {
376                         node->parent = XBC_NODE_MAX;
377                         sib = xbc_last_sibling(xbc_nodes);
378                         sib->next = xbc_node_index(node);
379                 } else {
380                         node->parent = xbc_node_index(last_parent);
381                         if (!last_parent->child) {
382                                 last_parent->child = xbc_node_index(node);
383                         } else {
384                                 sib = xbc_node_get_child(last_parent);
385                                 sib = xbc_last_sibling(sib);
386                                 sib->next = xbc_node_index(node);
387                         }
388                 }
389         } else
390                 xbc_parse_error("Too many nodes", data);
391 
392         return node;
393 }
394 
395 static inline __init struct xbc_node *xbc_add_child(char *data, u32 flag)
396 {
397         struct xbc_node *node = xbc_add_sibling(data, flag);
398 
399         if (node)
400                 last_parent = node;
401 
402         return node;
403 }
404 
405 static inline __init bool xbc_valid_keyword(char *key)
406 {
407         if (key[0] == '\0')
408                 return false;
409 
410         while (isalnum(*key) || *key == '-' || *key == '_')
411                 key++;
412 
413         return *key == '\0';
414 }
415 
416 static char *skip_comment(char *p)
417 {
418         char *ret;
419 
420         ret = strchr(p, '\n');
421         if (!ret)
422                 ret = p + strlen(p);
423         else
424                 ret++;
425 
426         return ret;
427 }
428 
429 static char *skip_spaces_until_newline(char *p)
430 {
431         while (isspace(*p) && *p != '\n')
432                 p++;
433         return p;
434 }
435 
436 static int __init __xbc_open_brace(char *p)
437 {
438         /* Push the last key as open brace */
439         open_brace[brace_index++] = xbc_node_index(last_parent);
440         if (brace_index >= XBC_DEPTH_MAX)
441                 return xbc_parse_error("Exceed max depth of braces", p);
442 
443         return 0;
444 }
445 
446 static int __init __xbc_close_brace(char *p)
447 {
448         brace_index--;
449         if (!last_parent || brace_index < 0 ||
450             (open_brace[brace_index] != xbc_node_index(last_parent)))
451                 return xbc_parse_error("Unexpected closing brace", p);
452 
453         if (brace_index == 0)
454                 last_parent = NULL;
455         else
456                 last_parent = &xbc_nodes[open_brace[brace_index - 1]];
457 
458         return 0;
459 }
460 
461 /*
462  * Return delimiter or error, no node added. As same as lib/cmdline.c,
463  * you can use " around spaces, but can't escape " for value.
464  */
465 static int __init __xbc_parse_value(char **__v, char **__n)
466 {
467         char *p, *v = *__v;
468         int c, quotes = 0;
469 
470         v = skip_spaces(v);
471         while (*v == '#') {
472                 v = skip_comment(v);
473                 v = skip_spaces(v);
474         }
475         if (*v == '"' || *v == '\'') {
476                 quotes = *v;
477                 v++;
478         }
479         p = v - 1;
480         while ((c = *++p)) {
481                 if (!isprint(c) && !isspace(c))
482                         return xbc_parse_error("Non printable value", p);
483                 if (quotes) {
484                         if (c != quotes)
485                                 continue;
486                         quotes = 0;
487                         *p++ = '\0';
488                         p = skip_spaces_until_newline(p);
489                         c = *p;
490                         if (c && !strchr(",;\n#}", c))
491                                 return xbc_parse_error("No value delimiter", p);
492                         if (*p)
493                                 p++;
494                         break;
495                 }
496                 if (strchr(",;\n#}", c)) {
497                         *p++ = '\0';
498                         v = strim(v);
499                         break;
500                 }
501         }
502         if (quotes)
503                 return xbc_parse_error("No closing quotes", p);
504         if (c == '#') {
505                 p = skip_comment(p);
506                 c = '\n';       /* A comment must be treated as a newline */
507         }
508         *__n = p;
509         *__v = v;
510 
511         return c;
512 }
513 
514 static int __init xbc_parse_array(char **__v)
515 {
516         struct xbc_node *node;
517         char *next;
518         int c = 0;
519 
520         do {
521                 c = __xbc_parse_value(__v, &next);
522                 if (c < 0)
523                         return c;
524 
525                 node = xbc_add_sibling(*__v, XBC_VALUE);
526                 if (!node)
527                         return -ENOMEM;
528                 *__v = next;
529         } while (c == ',');
530         node->next = 0;
531 
532         return c;
533 }
534 
535 static inline __init
536 struct xbc_node *find_match_node(struct xbc_node *node, char *k)
537 {
538         while (node) {
539                 if (!strcmp(xbc_node_get_data(node), k))
540                         break;
541                 node = xbc_node_get_next(node);
542         }
543         return node;
544 }
545 
546 static int __init __xbc_add_key(char *k)
547 {
548         struct xbc_node *node, *child;
549 
550         if (!xbc_valid_keyword(k))
551                 return xbc_parse_error("Invalid keyword", k);
552 
553         if (unlikely(xbc_node_num == 0))
554                 goto add_node;
555 
556         if (!last_parent)       /* the first level */
557                 node = find_match_node(xbc_nodes, k);
558         else {
559                 child = xbc_node_get_child(last_parent);
560                 if (child && xbc_node_is_value(child))
561                         return xbc_parse_error("Subkey is mixed with value", k);
562                 node = find_match_node(child, k);
563         }
564 
565         if (node)
566                 last_parent = node;
567         else {
568 add_node:
569                 node = xbc_add_child(k, XBC_KEY);
570                 if (!node)
571                         return -ENOMEM;
572         }
573         return 0;
574 }
575 
576 static int __init __xbc_parse_keys(char *k)
577 {
578         char *p;
579         int ret;
580 
581         k = strim(k);
582         while ((p = strchr(k, '.'))) {
583                 *p++ = '\0';
584                 ret = __xbc_add_key(k);
585                 if (ret)
586                         return ret;
587                 k = p;
588         }
589 
590         return __xbc_add_key(k);
591 }
592 
593 static int __init xbc_parse_kv(char **k, char *v, int op)
594 {
595         struct xbc_node *prev_parent = last_parent;
596         struct xbc_node *child;
597         char *next;
598         int c, ret;
599 
600         ret = __xbc_parse_keys(*k);
601         if (ret)
602                 return ret;
603 
604         child = xbc_node_get_child(last_parent);
605         if (child) {
606                 if (xbc_node_is_key(child))
607                         return xbc_parse_error("Value is mixed with subkey", v);
608                 else if (op == '=')
609                         return xbc_parse_error("Value is redefined", v);
610         }
611 
612         c = __xbc_parse_value(&v, &next);
613         if (c < 0)
614                 return c;
615 
616         if (op == ':' && child) {
617                 xbc_init_node(child, v, XBC_VALUE);
618         } else if (!xbc_add_sibling(v, XBC_VALUE))
619                 return -ENOMEM;
620 
621         if (c == ',') { /* Array */
622                 c = xbc_parse_array(&next);
623                 if (c < 0)
624                         return c;
625         }
626 
627         last_parent = prev_parent;
628 
629         if (c == '}') {
630                 ret = __xbc_close_brace(next - 1);
631                 if (ret < 0)
632                         return ret;
633         }
634 
635         *k = next;
636 
637         return 0;
638 }
639 
640 static int __init xbc_parse_key(char **k, char *n)
641 {
642         struct xbc_node *prev_parent = last_parent;
643         int ret;
644 
645         *k = strim(*k);
646         if (**k != '\0') {
647                 ret = __xbc_parse_keys(*k);
648                 if (ret)
649                         return ret;
650                 last_parent = prev_parent;
651         }
652         *k = n;
653 
654         return 0;
655 }
656 
657 static int __init xbc_open_brace(char **k, char *n)
658 {
659         int ret;
660 
661         ret = __xbc_parse_keys(*k);
662         if (ret)
663                 return ret;
664         *k = n;
665 
666         return __xbc_open_brace(n - 1);
667 }
668 
669 static int __init xbc_close_brace(char **k, char *n)
670 {
671         int ret;
672 
673         ret = xbc_parse_key(k, n);
674         if (ret)
675                 return ret;
676         /* k is updated in xbc_parse_key() */
677 
678         return __xbc_close_brace(n - 1);
679 }
680 
681 static int __init xbc_verify_tree(void)
682 {
683         int i, depth, len, wlen;
684         struct xbc_node *n, *m;
685 
686         /* Brace closing */
687         if (brace_index) {
688                 n = &xbc_nodes[open_brace[brace_index]];
689                 return xbc_parse_error("Brace is not closed",
690                                         xbc_node_get_data(n));
691         }
692 
693         /* Empty tree */
694         if (xbc_node_num == 0) {
695                 xbc_parse_error("Empty config", xbc_data);
696                 return -ENOENT;
697         }
698 
699         for (i = 0; i < xbc_node_num; i++) {
700                 if (xbc_nodes[i].next > xbc_node_num) {
701                         return xbc_parse_error("No closing brace",
702                                 xbc_node_get_data(xbc_nodes + i));
703                 }
704         }
705 
706         /* Key tree limitation check */
707         n = &xbc_nodes[0];
708         depth = 1;
709         len = 0;
710 
711         while (n) {
712                 wlen = strlen(xbc_node_get_data(n)) + 1;
713                 len += wlen;
714                 if (len > XBC_KEYLEN_MAX)
715                         return xbc_parse_error("Too long key length",
716                                 xbc_node_get_data(n));
717 
718                 m = xbc_node_get_child(n);
719                 if (m && xbc_node_is_key(m)) {
720                         n = m;
721                         depth++;
722                         if (depth > XBC_DEPTH_MAX)
723                                 return xbc_parse_error("Too many key words",
724                                                 xbc_node_get_data(n));
725                         continue;
726                 }
727                 len -= wlen;
728                 m = xbc_node_get_next(n);
729                 while (!m) {
730                         n = xbc_node_get_parent(n);
731                         if (!n)
732                                 break;
733                         len -= strlen(xbc_node_get_data(n)) + 1;
734                         depth--;
735                         m = xbc_node_get_next(n);
736                 }
737                 n = m;
738         }
739 
740         return 0;
741 }
742 
743 /**
744  * xbc_destroy_all() - Clean up all parsed bootconfig
745  *
746  * This clears all data structures of parsed bootconfig on memory.
747  * If you need to reuse xbc_init() with new boot config, you can
748  * use this.
749  */
750 void __init xbc_destroy_all(void)
751 {
752         xbc_data = NULL;
753         xbc_data_size = 0;
754         xbc_node_num = 0;
755         memblock_free(__pa(xbc_nodes), sizeof(struct xbc_node) * XBC_NODE_MAX);
756         xbc_nodes = NULL;
757         brace_index = 0;
758 }
759 
760 /**
761  * xbc_init() - Parse given XBC file and build XBC internal tree
762  * @buf: boot config text
763  * @emsg: A pointer of const char * to store the error message
764  * @epos: A pointer of int to store the error position
765  *
766  * This parses the boot config text in @buf. @buf must be a
767  * null terminated string and smaller than XBC_DATA_MAX.
768  * Return the number of stored nodes (>0) if succeeded, or -errno
769  * if there is any error.
770  * In error cases, @emsg will be updated with an error message and
771  * @epos will be updated with the error position which is the byte offset
772  * of @buf. If the error is not a parser error, @epos will be -1.
773  */
774 int __init xbc_init(char *buf, const char **emsg, int *epos)
775 {
776         char *p, *q;
777         int ret, c;
778 
779         if (epos)
780                 *epos = -1;
781 
782         if (xbc_data) {
783                 if (emsg)
784                         *emsg = "Bootconfig is already initialized";
785                 return -EBUSY;
786         }
787 
788         ret = strlen(buf);
789         if (ret > XBC_DATA_MAX - 1 || ret == 0) {
790                 if (emsg)
791                         *emsg = ret ? "Config data is too big" :
792                                 "Config data is empty";
793                 return -ERANGE;
794         }
795 
796         xbc_nodes = memblock_alloc(sizeof(struct xbc_node) * XBC_NODE_MAX,
797                                    SMP_CACHE_BYTES);
798         if (!xbc_nodes) {
799                 if (emsg)
800                         *emsg = "Failed to allocate bootconfig nodes";
801                 return -ENOMEM;
802         }
803         memset(xbc_nodes, 0, sizeof(struct xbc_node) * XBC_NODE_MAX);
804         xbc_data = buf;
805         xbc_data_size = ret + 1;
806         last_parent = NULL;
807 
808         p = buf;
809         do {
810                 q = strpbrk(p, "{}=+;:\n#");
811                 if (!q) {
812                         p = skip_spaces(p);
813                         if (*p != '\0')
814                                 ret = xbc_parse_error("No delimiter", p);
815                         break;
816                 }
817 
818                 c = *q;
819                 *q++ = '\0';
820                 switch (c) {
821                 case ':':
822                 case '+':
823                         if (*q++ != '=') {
824                                 ret = xbc_parse_error(c == '+' ?
825                                                 "Wrong '+' operator" :
826                                                 "Wrong ':' operator",
827                                                         q - 2);
828                                 break;
829                         }
830                         fallthrough;
831                 case '=':
832                         ret = xbc_parse_kv(&p, q, c);
833                         break;
834                 case '{':
835                         ret = xbc_open_brace(&p, q);
836                         break;
837                 case '#':
838                         q = skip_comment(q);
839                         fallthrough;
840                 case ';':
841                 case '\n':
842                         ret = xbc_parse_key(&p, q);
843                         break;
844                 case '}':
845                         ret = xbc_close_brace(&p, q);
846                         break;
847                 }
848         } while (!ret);
849 
850         if (!ret)
851                 ret = xbc_verify_tree();
852 
853         if (ret < 0) {
854                 if (epos)
855                         *epos = xbc_err_pos;
856                 if (emsg)
857                         *emsg = xbc_err_msg;
858                 xbc_destroy_all();
859         } else
860                 ret = xbc_node_num;
861 
862         return ret;
863 }
864 
865 /**
866  * xbc_debug_dump() - Dump current XBC node list
867  *
868  * Dump the current XBC node list on printk buffer for debug.
869  */
870 void __init xbc_debug_dump(void)
871 {
872         int i;
873 
874         for (i = 0; i < xbc_node_num; i++) {
875                 pr_debug("[%d] %s (%s) .next=%d, .child=%d .parent=%d\n", i,
876                         xbc_node_get_data(xbc_nodes + i),
877                         xbc_node_is_value(xbc_nodes + i) ? "value" : "key",
878                         xbc_nodes[i].next, xbc_nodes[i].child,
879                         xbc_nodes[i].parent);
880         }
881 }
882 

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